Being conscientious not only leads to a more successful life but also a longer one, a new study claims.

Scientists have discovered that high achievers such as company executives, Olympic athletes and even world leaders live on average up to four years longer than the general public.

Researchers believe that being both industrious and scrupulous at the same time appear to be the key to the extra longevity even though the individual's jobs may be more stressful than the average person.

The life-prolonging benefits of a "conscientious life" have come to light from a comparison of 20 previous studies which together matched the behaviour of 8,900 people with the age they died.

Dr Howard Friedman, at the Univeristy of California, analysed the results using a pyschologicial scale of conscientiousness which broke it down into multiple traits, including organisation, thoroughness, reliability, competence, order, dutifulness, ambition, self-discipline, and deliberation.

The results, published in the New Scientist, found that highly conscientious people lived on average two to four years longer than the norm.

This extra margin exceeds the effects of socioeconomic status and intelligence, which are also known to increase longevity.

Dr Friedman, who worked with Dr. Margaret Kern, said conscientious people do not live longer simply because they are boring or cautious, but admits they tend to "live lives that are more stable and less stressful".

"Yes it is true that conscientious folks are less like to smoke or drink to excess or take too many risks," he said.

"But it is also true that conscientious folks lead life patterns that are more stable and less stressful."

The study also found that orderly, responsible and reliable also lived longer.

"One of the studies we included looked at American presidents," said Dr Kern.

The first US president, George Washington, lived to be 67, double the life expectancy there at the time.

"Washington was very conscientious, yet he certainly didn't live a boring life."

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Well in Washington's era, infant mortality was ridiculously high, so that's not "double" the surviving adult life expectancy. As for CEOs and Olympians, aren't they more likely to be physically fit than average? Plus they didn't factor in self-perceived social status among CEOs and Olympians, which is important in longevity. Studies already show that winners of the Nobel prize, especially for Physics, live 2 years longer than those who don't because of the lifelong status boost. Were the nominees any less industrious? I don't think so.